1. Field of the Invention
The present invention relates to electrostatic generators, and more specifically, it relates to methods for enhancing the power output and lowering the output voltage of an electrostatic generator.
2. Description of Related Art
The “New Generation” electromechanical batteries (EMBs) now under development at Lawrence Livermore National Laboratory (LLNL) employ electrostatic generator/motors with a novel geometry. This document describes a design technique for the discharging circuits of those EMBs that can enhance their generator power output substantially over that achievable using conventional circuit design criteria.
The electrostatic generator/motors of our EMBs will employ stator and rotor condenser elements that consist of longitudinal arrays of metal tubes or rods (or azimuthally corrugated metal surfaces). Such condenser elements are described in U.S. patent application Ser. No. 13/96,678, titled “An Improved Electrode Geometry for Electrostatic Generators and Motors” filed Mar. 12, 2013, which is incorporated herein by reference. A schematic end-view of a portion of the stator and rotor of such an array when it is formed of metal tubes is shown in FIG. 1. Also shown in the figure is a section of a more conventional rotor/stator array involving parallel-plane electrodes with rounded edges. More specifically, four metal tubes of the rotor are shown on the left side of the figure. Reference number 10 refers to one such rotor tube. In the figure, each of the rotor tubes is shown to be aligned in the position of maximum capacity with a metal tube of the stator. Reference number 12 refers to one such stator tube. The right side of the figure shows four metal parallel-plane electrodes of the rotor, where each electrode is azimuthally aligned with a metal parallel-plane electrode of the stator. Reference number 14 is directed to one of the rotor electrodes and reference number 16 is directed to one of the stator electrodes. The figure is intended to illustrate a one-eighth section of each of the two different configurations. Thus, the actual embodiment of the tube type geometry would have axially oriented tubes spanning around the stator and the rotor with the given spacing. The same principle applies to the metal parallel-plane stator and rotor geometry.
Among the reasons for selecting the tube-tube geometry instead of parallel-plate geometry is the fact that its voltage-breakdown limit at a given gap is substantially enhanced over that of parallel-plate electrodes having the same gap. Furthermore, the tube-tube configuration has an important additional favorable characteristic that arises from its geometry, as follows: As the rotor elements move azimuthally away from the position of maximum capacity, the gap between the rotor and stator tubes increases monotonically until it reaches its maximum value when the rotor tubes are located midway azimuthally between two azimuthally adjacent stator tubes. As a consequence, the breakdown voltage, which always increases with increasing gap, also increases monotonically with rotation until the moving tubes reach a position corresponding to the maximum gap. As examination of FIG. 1 will show, this property (of a monotonically increasing gap under rotation) is not shared by the parallel-plate geometry, where the minimum gap initially actually decreases under rotation (because of its geometry) even though the inter-electrode capacity is decreasing.